JP2015133442A - Method for processing wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a divided wafer where a gap of chips is expanded.SOLUTION: A method for processing a wafer (W) includes the steps of: forming a dividing starting point along a dividing line (45) for a wafer supported by a first annular frame (F1), which is larger than the wafer, through an adhesive tape (T); applying external force to the dividing starting point to divide the wafer into individual chips (C), and extending the adhesive tape to expand a gap of the individual chips; and sticking a second annular frame (F2) having a proper size for the wafer on a region of the adhesive tape around the wafer inside of the first annular frame while heating the region, separating the first annular frame from the adhesive tape, and transferring the adhesive tape from the first annular frame to the second annular frame where the gap of the chips is maintained.

Description

  The present invention relates to a wafer processing method for dividing a semiconductor wafer into individual chips.

  In the manufacturing process of a semiconductor device, the surface of the wafer is partitioned into grid-like areas by dividing lines called streets, and semiconductor devices such as IC and LSI are formed in each area. As a method of dividing the wafer into individual chips, a method is used in which a weak layer (modified layer) is formed inside the wafer by irradiating the wafer with a laser beam, and the modified layer having the reduced strength is used as a starting point. It has been proposed (see, for example, Patent Document 1). In the processing method of Patent Document 1, an external force is applied to the fragile modified layer formed along the street, so that the wafer is divided into individual chips starting from the modified layer.

  In this case, an external force is applied to the wafer by expanding the adhesive tape attached to the annular frame with an expansion device or the like. When the adhesive tape is expanded, particularly the adhesive tape around the wafer is stretched, so that when the tension is released, a large slack occurs around the wafer. For this reason, there is a possibility that the adhesive tape is not stretched and the chips after the wafer split fixed to the adhesive tape are rubbed and damaged. Therefore, a method has also been proposed in which the tape is expanded using an annular frame that is slightly larger than the wafer size, and then transferred to an annular frame according to the wafer size in a state where tension is applied to the adhesive tape to eliminate slack. (For example, refer to Patent Document 2).

Japanese Patent No. 3408805 JP 2011-166002 A

  In the method described in Patent Document 2, an appropriate size annular frame is attached to the inside of a slightly larger annular frame while tension is applied to the adhesive tape, and then the tape is cut along the periphery of the appropriate size annular frame. By doing so, the larger annular frame is separated. When the pressure-sensitive adhesive tape is cut, the pressure-sensitive adhesive tape is peeled from the annular frame of an appropriate size by the contraction force when the tension of the pressure-sensitive adhesive tape is released. For this reason, the divided wafers could not be transported stably.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a wafer processing method capable of transporting a divided wafer with a gap between chips widened.

  A wafer processing method according to the present invention is a wafer processing method in which a plurality of devices are partitioned on a surface by a predetermined dividing line, the wafer is positioned at the center of the opening of the first annular frame, and a ductile adhesive tape is used. Adhesive tape adhering step for adhering the wafer to the first annular frame, a divided starting point forming step for forming divided starting points along a plurality of scheduled division lines, the adhesive tape adhering step and the divided starting point formation After carrying out the process, an expansion device comprising a cylindrical pressing member having a diameter smaller than the opening of the first annular frame and larger than the outer diameter of the wafer, and holding means for holding the first annular frame, After performing the expansion preparation step of placing the wafer fixed to the first annular frame, and the expansion preparation step, the pressing member and the holding means are relatively moved in the axial direction to move the wafer. Expanding the pressure-sensitive adhesive tape to which C is attached, dividing the wafer into individual chips along the planned division line on which the division starting points are formed, and forming a gap between the chips; A second annular frame preparation step of preparing a second annular frame having an outer diameter that can be accommodated in the opening of the first annular frame and an opening that can accommodate a wafer in which a gap is formed between the chips. And after the adhesive tape expanding step, the second annular frame is mounted on the adhesive tape at a position where the wafer adhered to the first annular frame is at the center of the opening of the second annular frame. An annular frame transfer step of cutting and sticking the adhesive tape along the second annular frame to transfer the wafer to the second annular frame via the adhesive tape. In beam sorting process, characterized by attaching said second annular frame PSA on the tape while heating the pressure-sensitive adhesive tape by said second annular frame or the pressing member.

  According to this configuration, the area of the adhesive tape around the wafer inside the first annular frame is expanded by the relative movement of the holding means and the pressing means. By expanding the adhesive tape, an external force is applied to the starting point of the wafer division, and the wafer is divided into individual chips along the planned division line. Then, the second annular frame is attached to the area of the adhesive tape around the wafer inside the first annular frame, and the wafer is transferred to the second annular frame. At this time, since the pressure-sensitive adhesive tape is heated, the holding force of the pressure-sensitive adhesive tape is increased, and the pressure-sensitive adhesive tape is satisfactorily attached to the second annular frame. Therefore, even if the first annular frame is separated from the adhesive tape and the tension of the adhesive tape is released and a strong contraction force is generated, the adhesive tape is prevented from peeling from the second annular frame. Then, the adhesive tape is transferred from the first annular frame to the second annular frame with a chip gap secured, and thereafter the wafer supported by the second annular frame can be stably conveyed. It is.

  Further, in the wafer processing method, the adhesive tape expanding step includes a step of attaching a bar-shaped dividing jig that is equal to or larger than the diameter of the wafer and disposed in the cylindrical pressing member to the division line of the wafer. It is made to contact through a tape and a bending stress is applied to the division planned line to divide into individual chips.

  According to the present invention, since the second annular frame is attached to the adhesive tape while heating the adhesive tape, the holding force of the adhesive tape with respect to the annular frame is increased, and the first annular frame is separated from the adhesive tape. Even in this case, the adhesive tape is prevented from peeling off from the second annular frame. Therefore, the wafer can be transferred in a state in which the gap between the chips is ensured.

It is a figure which shows each process of the processing method which concerns on this Embodiment. It is a figure which shows each process of the processing method which concerns on this Embodiment. It is a figure which shows the cyclic | annular frame transfer process of the processing method which concerns on this Embodiment. It is a figure which shows the wafer after the cyclic | annular flame | frame transfer which concerns on this Embodiment. It is explanatory drawing of the sticking state of the 2nd annular frame with respect to the adhesive tape which concerns on this Embodiment. It is a figure which shows an example of the adhesive tape expansion process of the wafer which concerns on a modification.

  Hereinafter, a wafer processing method according to the present embodiment will be described. In the wafer processing method according to the present embodiment, an adhesive tape sticking process, a division starting point forming process, an expansion preparation process, an adhesive tape expansion process, a second annular frame preparation process, and an annular frame transfer process are performed on the wafer. To be implemented. In the adhesive tape attaching step, the wafer W is attached to the first annular frame F1 that is slightly larger than the wafer size via the adhesive tape T (see FIG. 1A). In the division starting point forming step, the modified layer 43 along the division line 45 is formed as a division starting point inside the wafer W by laser processing (see FIG. 1B).

  In the expansion preparation step, the first annular frame F1 is held by the holding means 22, and the cylindrical pressing member 23 is positioned in the area of the adhesive tape T around the wafer W inside the first annular frame F1 (see FIG. 2A). In the adhesive tape expansion process, the adhesive tape T is expanded by the relative movement of the holding means 22 and the pressing member 23, and the wafer W is divided into individual chips C using the modified layer 43 as a division starting point (see FIG. 2B). In the second annular frame preparation step, a second annular frame F2 that is smaller than the first annular frame F1 and has an appropriate size for the wafer W is prepared (see FIG. 2C).

  In the annular frame transfer step, the second annular frame F2 is adhered to the area of the adhesive tape T while the area of the adhesive tape T around the wafer W is heated inside the first annular frame F1 ( (See FIG. 3). As a result, the holding force of the adhesive tape T increases and the adhesive tape T is strongly attached to the second annular frame F2. Even if the first annular frame F1 is cut off from the adhesive tape T, the adhesive tape T is not peeled off from the second annular frame F2 by the contraction force of the adhesive tape T, and the second annular frame F1 is removed from the first annular frame F1. The wafer W is successfully transferred to the annular frame F2.

  Details of the wafer processing method according to the present embodiment will be described below with reference to FIGS. FIG. 1A is a diagram illustrating an example of an adhesive tape attaching process according to the present embodiment. FIG. 1B is a diagram showing an example of the division start point forming step according to the present embodiment. FIG. 2A is a diagram illustrating an example of an expansion preparation process according to the present embodiment. FIG. 2B is a diagram showing an example of an adhesive tape expansion process according to the present embodiment. FIG. 2C is a diagram illustrating an example of a second annular frame preparation process according to the present embodiment. 3A and 3B are diagrams illustrating an example of the annular frame transfer process according to the present embodiment. FIG. 4 is a view showing the wafer after the transfer of the annular frame according to the present embodiment.

  As shown in FIG. 1A, in the adhesive tape attaching step, the wafer W is attached to the first annular frame F1 via the adhesive tape T. The wafer W is formed in a substantially disk shape from silicon, gallium arsenide, or the like. On the surface 41 of the wafer W, a grid-like division planned line 45 is provided, and a device D such as an IC or LSI is formed in each region partitioned by the division planned line 45. On the outer edge of the wafer W, a notch 46 indicating a crystal orientation is formed. The wafer W is not limited to a semiconductor wafer, and may be an optical device wafer in which an optical device such as an LED is formed on a ceramic, glass, or sapphire inorganic material substrate.

  As the first annular frame F1, an annular frame that is slightly larger in diameter than the wafer size is used. For example, in the case of an 8-inch wafer, an annular frame for a 12-inch wafer is used. A circular adhesive tape T having ductility is attached to the first annular frame F1, and the adhesive surface of the adhesive tape T is exposed from the central opening of the first annular frame F1. And the wafer W is affixed on the adhesive surface of the adhesive tape T in the state which positioned the wafer W in the opening center of the 1st annular frame F1. The wafer W is carried into the laser processing apparatus 11 (see FIG. 1B) while being supported inside the first annular frame F1 via the adhesive tape T.

  In addition, an adhesive tape sticking process may be implemented manually by an operator, or may be carried out by a not-shown sticking device. The pressure-sensitive adhesive tape T is made of polyvinyl chloride (PVC) as a base material and heated to 60 degrees or more to improve the fluidity of the pressure-sensitive adhesive layer, so that the annular frame (second annular frame F2 (see FIG. 3) )) To increase the holding power. In addition, the adhesive tape T should just be comprised so that the fluidity | liquidity of an adhesive layer may be improved to such an extent that the retention strength with respect to a cyclic | annular flame | frame increases by being formed with the material which has ductility and heating to predetermined temperature.

  As shown to FIG. 1B, a division | segmentation starting point formation process is implemented after an adhesive tape sticking process. In the division starting point forming step, the wafer W is held on the chuck table 12 of the laser processing apparatus 11 via the adhesive tape T, and the first annular frame F1 around the wafer W is held by the clamp unit 13. Further, the exit of the laser irradiation unit 14 is positioned on the division line 45 of the wafer W, and the laser beam is irradiated to the wafer W by the laser irradiation unit 14. The laser beam has a wavelength that is transmissive to the wafer W and is adjusted so as to be condensed inside the wafer W.

  Then, the laser irradiation means 14 is relatively moved with respect to the wafer W while the condensing point of the laser beam is adjusted, whereby the modified layer 43 along the planned division line 45 is formed inside the wafer W. In this case, first, the condensing point is adjusted in the vicinity of the back surface 42 of the wafer W, and laser processing is performed so that the lower end portion of the modified layer 43 is formed along all the division lines 45. Then, each time the height of the condensing point is moved up, the laser processing is repeated along the scheduled division line, whereby the modified layer 43 having a predetermined thickness is formed inside the wafer W. In this way, a division starting point along the division line 45 is formed inside the wafer W.

  The modified layer 43 is a region in which the density, refractive index, mechanical strength, and other physical characteristics inside the wafer W are different from the surroundings due to laser beam irradiation, and the strength is lower than the surroundings. . The modified layer 43 is, for example, a melt treatment region, a crack region, a dielectric breakdown region, or a refractive index change region, and may be a region where these are mixed.

  In the present embodiment, the modified layer 43 is formed as the division starting point, but the present invention is not limited to this configuration. A processing groove may be formed as a division starting point by a cutting blade or ablation processing. Ablation means that when the irradiation intensity of a laser beam exceeds a predetermined processing threshold, it is converted into electronic, thermal, photochemical and mechanical energy on the solid surface, resulting in neutral atoms, molecules, positive and negative A phenomenon in which ions, radicals, clusters, electrons, and light are explosively emitted and the solid surface is etched. The wafer W on which the division starting point is formed is carried into the expansion device 21 (see FIG. 2).

  As shown in FIG. 2A, an expansion preparation step is performed after the division start point formation step. In the expansion preparation step, the wafer W is placed on the expansion device 21 and the expansion of the wafer W is prepared. The expansion device 21 is provided with a holding means 22 including an annular table 25 and a clamp portion 26, and the first annular frame F 1 on the annular table 25 is held by the clamp portion 26. Inside the annular table 25, a cylindrical pressing member 23 having a diameter smaller than the opening of the first annular frame F1 and larger than the outer diameter of the wafer W is disposed. At the upper end portion of the cylindrical pressing member 23, a contact portion 27 that contacts the adhesive tape T from below is provided, and a plurality of roller portions 28 are provided on the outer peripheral side of the contact portion 27 in the circumferential direction. Is provided.

  As shown in FIG. 2B, an adhesive tape expansion process is performed after the expansion preparation process. In the adhesive tape expansion step, the cylindrical pressing member 23 is raised relative to the holding means 22 by lowering the first annular frame F <b> 1 together with the annular table 25. As a result, the adhesive tape T to which the wafer W is adhered is expanded in the radial direction, and an external force is applied to the modified layer 43 (see FIG. 2A) of the wafer W via the adhesive tape T. The wafer W is divided into individual chips C along the division line 45 (see FIG. 2A), starting from the modified layer 43 with reduced strength. The adhesive tape T is expanded until the adjacent chips C are completely separated, and a gap is formed between the adjacent chips C.

  At this time, since the adhesive tape T is in rolling contact with the plurality of roller portions 28 at the outer peripheral edge of the cylindrical pressing member 23 (contact portion 27), friction or the like during expansion of the adhesive tape T is suppressed. In the adhesive tape expanding step, the adhesive tape T is expanded by lowering the holding means 22 with respect to the cylindrical pressing member 23. However, the present invention is not limited to this configuration. The adhesive tape T only needs to be expanded by the relative movement of the cylindrical pressing member 23 and the holding means 22 in the axial direction. For example, the cylindrical pressing member 23 may rise relative to the holding means 22 to expand the adhesive tape T, or the cylindrical pressing member 23 rises and the holding means 22 descends to cause the adhesive tape T to rise. May be extended.

  As shown in FIG. 2C, a second annular frame preparation step is performed after the adhesive tape expansion step. In the second annular frame preparation step, the second annular frame F2 is prepared by conveying the second annular frame F2 above the cylindrical pressing member 23 by the frame conveying means 31. The second annular frame F2 is formed in an appropriate size for the wafer W, has an outer diameter that can be accommodated in the opening of the first annular frame F1, and can accommodate the wafer W provided with a gap between the chips C. Has an opening. Further, the frame conveying means 31 holds the second annular frame F2 by the frame holding part 32 incorporating the heater 33, and conveys the second annular frame F2 while heating.

  As shown in FIG. 3A, an annular frame transfer step is performed after the second annular frame preparation step. In the annular frame transfer process, the second annular frame F2 is placed on the adhesive tape T at the position where the wafer W supported by the first annular frame F1 is the center of the opening of the second annular frame F2. Affixed. In this case, the second annular frame F2 heated by the frame conveying means 31 is attached to the adhesive tape T, whereby the adhesive tape T is heated to a predetermined temperature (60 degrees in this embodiment) or more. As a result, the holding force of the adhesive tape T is increased, and the adhesive tape T is favorably attached to the second annular frame F2. When the second annular frame F <b> 2 is attached to the adhesive tape T, the frame transport unit 31 is retracted from above the expansion device 21. The adhesive tape T is cooled by separating the frame holding part 32 from the second annular frame F2.

  As shown in FIG. 3B, in the annular frame transfer process, the wafer transfer means 35 is moved above the expansion device 21 in place of the frame transfer means 31. The wafer transfer means 35 is provided with a frame holding portion 36 corresponding to the second annular frame F <b> 2, and a cutter portion 37 is provided on the outer peripheral side of the frame holding portion 36. The second annular frame F2 is held by the frame holding part 36, and the adhesive tape T is cut by the cutter part 37 along the outer shape of the second annular frame F2. At this time, since the adhesive tape T is tensioned by tape expansion, a strong contraction force is generated by cutting the adhesive tape T. However, since the adhesive tape T is strongly adhered to the second annular frame F2, the adhesive tape T is prevented from peeling off from the second annular frame F2. With the above configuration, as shown in FIG. 4, each chip C together with the adhesive tape T is transferred from the first annular frame F <b> 1 to the second annular frame F <b> 2 while maintaining the gap between the chips C. .

  In addition, the heater 33 should just be the structure which can heat the adhesive tape T in an annular frame transfer process, and an attachment position, a shape, etc. are not specifically limited. For example, the heater 33 may be provided at the contact portion 27 of the pressing member 23, or the heater 33 may be provided at both the frame conveying means 31 and the contact portion 27 of the pressing member 23. Moreover, the cutter part 37 should just be able to cut | disconnect the adhesive tape T along the external shape of the 2nd cyclic | annular frame F2 in a cyclic | annular frame transfer process, and an attachment position, a shape, etc. are not specifically limited. For example, the cutter part 37 may be provided in the contact part 27 of the pressing member 23, or the cutter part 37 may be provided in a device dedicated to cutting other than the wafer transfer means 35.

  Here, with reference to FIG. 5, the sticking state of the 2nd annular frame with respect to an adhesive tape is demonstrated in detail. FIG. 5 is an explanatory diagram of a state in which the second annular frame is attached to the adhesive tape according to the present embodiment. FIG. 5A shows a state where the second annular frame is attached to the adhesive tape, and FIG. 5B shows a state where the first annular frame is separated from the adhesive tape.

  As shown in FIG. 5A, the adhesive tape T is supported by the contact portion 27 of the cylindrical pressing member 23 in the state where the adhesive tape T is expanded as described above. Then, the second annular frame F 2 is conveyed while being heated by the heater 33 of the frame conveying means 31, and the second annular frame F 2 is pressed against the adhesive layer 47 of the adhesive tape T toward the contact portion 27. Thereby, the adhesive tape T is heated by the high-temperature second annular frame F2. When the adhesive tape T is heated to a predetermined temperature (60 ° C. in this embodiment) or higher, the adhesive layer 47 of the adhesive tape T flows and enters the fine uneven surface of the lower surface 48 of the second annular frame F2.

  As a result, the contact area between the adhesive tape T and the second annular frame F2 increases, and the holding force of the adhesive tape T with respect to the second annular frame F2 increases. In particular, since the adhesive layer 47 of the adhesive tape T enters the fine uneven surface of the second annular frame F2, the adhesive tape T is caught on the second annular frame F2, and the radial deformation of the adhesive tape T occurs. Is strongly suppressed.

  As shown in FIG. 5B, when the tensioned adhesive tape T is cut, the tension of the adhesive tape T is released and a strong contracting force 61 is generated in the adhesive tape T. At this time, a holding force 62 of the adhesive tape T with respect to the second annular frame F2 is generated in a direction opposite to the contraction force 61 of the adhesive tape T. Since the holding force 62 of the adhesive tape T with respect to the second annular frame F2 is strengthened in a direction to suppress the radial deformation of the adhesive tape T, the contraction force 61 of the adhesive tape T causes the second annular frame F2 to move away from the second annular frame F2. The adhesive tape T does not peel off. Therefore, when the adhesive tape T is transferred from the first annular frame F1 (see FIG. 3A) to the second annular frame F2, gaps between the individual chips C are secured.

  As described above, in the processing method of the wafer W according to the present embodiment, the region of the adhesive tape T around the wafer W inside the first annular frame F1 moves relative to the holding means 22 and the pressing member 23. Extended by By the expansion of the adhesive tape T, an external force is applied to the modified layer 43 of the wafer W, and the wafer W is divided into individual chips C along the division line 45. Then, the second annular frame F2 is attached to the area of the adhesive tape T around the wafer W inside the first annular frame F1, and the wafer W is transferred to the second annular frame F2. At this time, since the adhesive tape T is heated, the holding force of the adhesive tape T is increased and the adhesive tape T is satisfactorily attached to the second annular frame F2. Therefore, even if the first annular frame F1 is separated from the adhesive tape T and the tension of the adhesive tape T is released and a strong contraction force is generated, the adhesive tape T is prevented from peeling off from the second annular frame F2. The Then, the adhesive tape T is transferred from the first annular frame F1 to the second annular frame F2 in a state where a gap between the chips C is secured, and then the wafer W supported by the second annular frame F2 is stabilized. Can be transported.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the wafer W processing method according to the present embodiment, the adhesive tape T is expanded by the expansion device 21 to divide the wafer W into individual chips C and widen the interval between adjacent chips C. However, it is not limited to this configuration. As shown in the modified example of FIG. 6, the wafer W may be divided into individual chips C by breaking and then the interval between adjacent chips C may be increased by tape expansion.

  Hereinafter, with reference to FIG. 6, the processing method of the wafer W which concerns on a modification is demonstrated. FIG. 6 is a diagram illustrating an example of a wafer adhesive tape expansion process according to a modification. In addition, in the processing method of the wafer W which concerns on a modification, since each process other than an adhesive tape expansion process is the same as that of the said embodiment, an adhesive tape expansion process is mainly demonstrated.

  As shown to FIG. 6A, an adhesive tape expansion process is implemented after an adhesive tape sticking process, a division | segmentation starting point formation process, and an expansion preparation process. In the adhesive tape expansion process according to the modified example, first, the breaking process is performed by the dividing jig 51 disposed inside the cylindrical pressing member 23 of the expansion device 21. The dividing jig 51 is formed in a bar shape having a diameter equal to or larger than the diameter of the wafer W, and is configured to contact the wafer W via the adhesive tape T. The upper surface of the split jig 51 is provided with a step by an upper support surface 52 and a lower support surface 53 along the extending direction, and a linear suction port 54 is formed at the boundary portion of the step.

  In the breaking process, the dividing jig 51 is moved in a direction orthogonal to the planned dividing line 45 while the adhesive tape T is sucked by the suction port 54. When the planned division line 45 of the wafer W is positioned on the edge 55 of the upper support surface 52, bending stress acts along the planned division line 45 of the wafer W by the suction force from the suction port 54. As a result, the modified layer 43 of the wafer W is used as a division starting point to divide the wafer W. The wafer W is divided into individual chips C by positioning the dividing jig 51 on all the division lines 45.

  As shown to FIG. 6B, in the adhesive tape expansion process which concerns on a modification, a tape expansion process is implemented after a braking process. In the adhesive tape expansion step, the cylindrical pressing member 23 is raised relative to the holding means 22 so that the adhesive tape T is expanded in the radial direction, and a gap is formed between the individual chips C. After the adhesive tape expansion step, a second annular frame preparation step and an annular frame transfer step are performed as in the above embodiment.

  In the adhesive tape expansion process according to the modification, the wafer W is divided by the dividing jig 51 having a step, but the present invention is not limited to this structure. The dividing jig 51 may be configured in any way as long as it is arranged inside the cylindrical pressing member 23 and can divide the wafer W along the scheduled dividing line 45. For example, the upper surface of the dividing jig 51 may be formed in a wedge shape, and the dividing jig 51 may be divided by pushing up the wafer W from the adhesive tape T side.

  Moreover, in the processing method of the wafer W which concerns on this Embodiment, although it was set as the structure by which a division | segmentation starting point formation process is implemented after an adhesive tape sticking process, it is not limited to this structure. An adhesive tape sticking process may be implemented after a division starting point formation process.

  In the processing method of the wafer W according to the present embodiment, a frame that is slightly larger than the wafer size is used as the first annular frame F1, and an appropriate size of the wafer W is used as the second annular frame F2. Although a frame was used, it is not limited to this configuration. The first annular frame F1 may be of a size that allows the second annular frame F2 to be disposed inside, and the second annular frame F2 may be of a size that allows the wafer W to be disposed inside.

  As described above, the present invention has the effect that it can be transported in a state where a gap between chips after the wafer is divided, and is particularly useful for a wafer processing method for dividing a semiconductor wafer into individual chips. It is.

DESCRIPTION OF SYMBOLS 11 Laser processing apparatus 12 Chuck table 14 Laser irradiation means 21 Expansion apparatus 22 Holding means 23 Press member 27 Contact part 31 Frame conveyance means 33 Heater 35 Wafer conveyance means 37 Cutter part 41 Wafer surface 42 Wafer back surface 43 Modified layer ( Split start)
45 Line to be divided 47 Adhesive layer 51 Dividing jig C Chip D Device F1 First annular frame F2 Second annular frame T Adhesive tape W Wafer

Claims (2)

A method of processing a wafer in which a plurality of devices are partitioned on a surface by dividing lines,
Positioning the wafer in the center of the opening of the first annular frame, and sticking the wafer to the first annular frame via a ductile adhesive tape,
A division start point forming step of forming a division start point along a plurality of division planned lines;
After carrying out the adhesive tape attaching step and the split starting point forming step, a cylindrical pressing member having a diameter smaller than the opening of the first annular frame and larger than the outer diameter of the wafer, and the first annular frame An expansion preparation step of placing a wafer fixed to the first annular frame on an expansion device comprising a holding means for holding;
After carrying out the expansion preparation step, the pressing member and the holding means are moved relative to each other in the axial direction to expand the adhesive tape to which the wafer is adhered, and the division planned line on which the division starting point is formed. And an adhesive tape expansion process that divides the chip into individual chips and forms a gap between the chips,
A second annular frame preparation step of preparing a second annular frame having an outer diameter that can be accommodated in the opening of the first annular frame and an opening that can accommodate a wafer in which a gap is formed between the chips. When,
After performing the adhesive tape expansion step, the second annular frame is placed on the adhesive tape at a position where the wafer adhered to the first annular frame is at the center of the opening of the second annular frame. Attaching and cutting the adhesive tape along the second annular frame to transfer the wafer to the second annular frame via the adhesive tape; and
In the annular frame transfer step, the second annular frame is stuck on the adhesive tape while the adhesive tape is heated by the second annular frame or the pressing member. .   The adhesive tape expanding step is performed by bringing a bar-shaped dividing jig that is equal to or larger than the diameter of the wafer and disposed in the cylindrical pressing member into contact with the planned dividing line of the wafer via the adhesive tape. 2. The wafer processing method according to claim 1, wherein the dividing line is divided into individual chips by applying a bending stress to the dividing line.

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